Section insulator with magnetic blow-out



May 17, 1938. r c. c. WHITTAKER SECTION INSULATOR WITH MAGNETIC BLOW-OUT Filed Feb. 20, 1957- 2 Sheets-Sheet l WITN ESSE S: INVENTOR May 17, 1938. c. c. WHlTTAKERi SECTION INSULATOR WITH MAGNETIC BLOW-O UT 2 Sheets-Sheet 2 Filed Feb. 20, 1937 'i l RNEY INVENTbR Char/es CT W/Yif/axen WITNESSES;

Patented May 17, 1938 UNITED STATES PATENT OFFICE W-OUT Charles C. Whittaker, Pittsburgh, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 20, 1937, Serial No. 126,852

14 Claims.

My invention relates, generally, to overhead trolley systems and it has reference ,in particular to an improvement in section insulators for overhead trolley systems.

It has been found in practice that the are drawn by a current collector in passing from a live trolley wire to the insulating runner member of a, section insulator is particularly destructive to the insulating material of the body of the insulator. The arc, being drawn along and beneath the insulating member, and having a great tendency to rise because of the currents of heated air about it, is maintained in intimate contact with the insulating member. The insulating material is thereby subjected to, and damaged by the heating effect of the arc, and in due time is so weakened that it either fails electrically by flashing over, or mechanically by rup turing through the section most subjected to heat of the arc. Such failures are particularly expensive, entailing not only great difficulty in replacing the section insulator, but also disrupting schedules and generally delaying traffic while the replacement is being made.

By utilizing the are blowing effect of the magnetic field about a current-carrying conductor to downwardly repel an are drawn by a current collector along the insulating member, the life of the insulating material may be greatly increased. Further, by positioning a number of metallic are members along the insulating member, so as to break an are drawn by a current collector into a plurality of short, serially related arcs, and by so directing the flow of the arc current between adjacent arcs, that it is substantially perpendicular to the direction of the arc, a plurality of lo-' cally concentrated arc repelling magnetic fields may be built up. The are is thereby not only broken into a number of smaller arcs which may be more readily extinguished, but the metallic are members provide a cooling medium for the arc stream, further aiding in its extinction. By increasing the resistance of the metallic path of the arc current through the are members on the section insulator, the current flow in the are may be materially limited, and further, by utilizing the are blowing effect of the magnetic field set up by the flow of arc current in a resistance element, the thus already weakened arc may be more readily extinguished.

It is, therefore, generally an object of my invention to provide for materially reducing the harmful effects of an electric are on the insulating member of a section insulator.

Another object of my invention is to provide a renewable arc member for a sectioninsulator, wherein a directed arc current flow is secured adjacent to the arc to materially increase the blowout eiiect of the magnetic field'produced by the fiow of arc current.

A further object of my invention is to provide metallic are members for the insulating member of a section insulator, whereby an are drawn by a current collector is broken into a plurality of serially related arcs.

Another object of my invention is to provide for directing the flow of an arc current in spaced metallic are members on a section insulator so that the arc is repelled from the insulating memher by the magnetic field set up by current flow in the members adjacent to the arc.

Still another object of my invention is to provide for materially limiting the flow of are current on a, section insulator, the current limiting means being disposed to repel the restricted'arc from contact with the insulating member.

A yet further object of my invention is to provide for increasing the life of a section insulator by reducing the are drawn by a current collector to a plurality of small, serially related arcs, such that the direction of arc current flow adjacent to each arc produces a magnetic field disposed to repel the arc from the insulating member.

A still further object of my invention is to provide arc extinguishing means for a section insulator which shall be simple and economical to manufacture, easily installed, and inexpensive to maintain.

Other objects of my invention will in part be obvious, and in part appear hereinafter.

My invention, accordingly, is disclosed in the embodiments hereof shown in the accompanying drawings, and comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and in the scope of the application which will be indicated in the appended claims.

In a preferred form of my invention, the are drawn by a current collector in passing from a live section of the trolley wire to the insulating member of a section insulator may be broken into a plurality of serially related arcs by auxiliary metallic are members which are disposed along the' insulating member of the section insulator. The path of the arc current through these auxiliary are members may be so directed by metallic conductors associating or connecting spaced runner portions of the auxiliary are members that the magnetic field about a contherefore greatly increased, and expensive replacements and traffic tieups are avoided.

For a more complete understanding of the nature and the scope of my invention, reference may be had to the following detailed description,

taken in connection with the accompanying drawings, in which:

Figure 1 is a side elevation view of a section insulator embodying the principal features of my invention;

Fig. 2 is a plan view of the section insulator of Fig. 1;

Fig. 3 is a sectional View of the section insulator of Fig. 1 taken along the line IIIIII of Fig. 1;

Fig. 4 is a sectional view of the section insulator of Fig. 1 taken along the line. IVIV of Fig. 1;

Fig. 5 is an end elevation view of an arc member, the side elevation view of which is shown in association with an end member in Fig. 1,

Fig. 6 is a side elevation View of a section insulator embodying another form of my invention;

Fig. '7 is a plan view of the section insulator of Fig. 6;

Fig. 8 is a sectional View of the section insulator of Fig. 6 taken along the line VIII--VIII of Fig. 6, and

Fig. 9 is a side elevation View of a portion of a section insulator showing an alternate form of the invention of Fig. 1.

Referring more particularly to Figs. 1 and 2, it may be seen that the reference numeral M denotes generally a section insulator comprising an insulating member I I, which may be constructed in any desired manner, comprising for example, an insulating material having a reinforcing core I 2 as shown in Figs. 3 and 4. End members 53 and I4, which are adapted to support or position the section insulator in an overhead trolley system, may be secured in engagement with the insulating member II. An arc member I5, removably associated with the end member l3, auxiliary arc members I6, disposed in spaced relation along the insulating member II, and an insulating runner member I8 may be adapted to provide for smooth passage of a current collector along the section insulator. The runner member I8 may be secured to the body member I I in any desired manner, such as by a connecting strap I 9 and engagement with the runner portion of an auxiliary arc member I6.

In the form illustrated, the section insulator III is adapted for use in a loop system, wherein vehicular traffic passes along the line in one direction only, however, it is to be understood that the principles of the invention may also be to other forms of section insulators. In this instance, the section insulator is effective to materially repel an are from the insulating member and extinguish said are as a current collector passes along the insulator from left to right. The renewable arc member I5, which is disposed to be removably associated with the end member I3, may com prise generally a U-shaped channel member, as may be more clearly seen by referring to Fig. 5, having a runner portion 20 to provide a wearing and conducting surface for passage of a current collector (not shown). The upstanding sides 2| and 22 may be slotted for securing the member I5 in engagement with the end member I3 by means of the bolts 24 and 25, which are primarily adapted to secure the end member 53 in engagement with the insulating member I I. An upwardly extending transverse slot 28 in the arc member is disposed to form a downwardly extending arc tip 30 at one end of the member, wherein the flow of current, as a current collector (not shown) leaves the: arc tip 30, in moving along the insulator from left to right, must be directed in the downward direction.

To aid in disrupting an are drawn by the cur rent collector from the arc tip 39 as it passes along the section insulator, auxiliary metallic arc members I5 may be disposed in spaced relation along the body member II of the section insu lator. may comprise a metallic member having a substantially U-shaped cross-section, as may be. seen by referring to Fig. 3, provided with a runner portion on the underside, and upwardly extending side flanges 33 and 34, adapted to be secured about the insulating member II. An upwardly extending transverse slot 35 may be provided in the arcing member, extending through the runner portion and up into the side flanges 33 and 34, thus dividing the runner portion of the member i5 into a pair of related runner portions 35 and 31, associated by metallic conducting arms 38 and 39 on each side of the insulating member. By making the depth of the slot 35 substantially greater than the width, an upwardly looped metal conducting path, comprising the connecting arms 38 and 39, may be provided between the related runner portions 36 and 31. The side flanges 33 and 34 are adapted to be secured in engagement about the insulating member I I at upper ends by the transverse bolt member 48, thus maintaining the auxiliary arc member I 6 in operating relation on the body member 11.

As a current collector passes from the runner portion 36 to the runner portion 31 of an auxiliary arc member I6, the current of the arc sustained between the arc tip 30 and the runner portion 36 will follow the metallic conducting path 38-39 between the runner portions. As

the current collector progresses still further along the section insulator, and passes to an adjacent arc member I6, an arc will be drawn from the runner portion 3? to the runner portion 36 of the adjacent auxiliary arc member. It may be seen, therefore, that in general, the direction of current flow adjacent to the are drawn between the members is substantially perpendicular to the axis of the arc, thus resulting in a magnetic field between adjacent arc members which tends to force the arc downward, not only repelling it from the insulating member, but exerting a blowout force to extinguish the arc itself.

In another form of my invention, which is illustrated in Figs. 6, 7, and 8, an elongated coiled resistance element comprising similar sections 45 and 46 may be disposed in divided relation adjacent to opposite sides of the insulating member II, and associated in series circuit relation with an arc member I5 and a U-shaped auxiliary arc member 41, which may be provided with a runner portion 48 on the underside, similar to the'runner portion 36 of the auxiliary arc member as shown in Fig. 3. The sections 45 and 46 of the resistance element may be secured to the In general, an auxiliary arc member I 6 insulating member II in any desired manner, such as by positioning the auxiliary arc member 4! in spaced relation to the arc member l5 with upstanding sides 49 and 50 about the insulating member H and the sections 45 and 46 of the resistance element, and securing them in engagement by a transverse through bolt 5|, as illustrated in Fig. 8. A similar U-shaped clamp member 4'! may be positioned in engagement with the other ends of the coiled resistance sections to aid in securing them firmly to the insulating member H.

As a current collector proceeds along the section insulator from left to right, the current flow in the arc tip 30 of the arc member I5 is directed downwards as the current collector leaves the arc tip, thus building up a downwardly repelling magnetic field which acts to extinguish any are drawn therefrom by the current collector. When the current collector makes contact with the auxiliary arc member 41, current will be drawn through the coiled resistance element sections 45 and 46, thus reducing the arc current drawn from the arc tip 30, but still maintaining the arc from the arc tip 30 as the auxiliary arc member 41 will be at a substantially lower potential than the arc tip 30, because of the resistance drop in the coiled resistance element sections 45 and it. At the same time, a concentrated magnetic field will be built up by the current flowing through the sections of the coiled resistance element. As the current collector leaves the auxiliary arc member 41 and moves on to the insulating runner member I8, the are it draws will be substantially limited by the resistance of the coiled element sections 65 and 56, and will further be subjected to the concentrated magnetic field set up by the plurality of turns in the resistance element sections. The arc drawn, therefore, is not only limited by the resistance element, but is broken into a pair of related arcs, each of which is subjected to the blowout effect of separate magnetic fields, thus facilitating ready extinction of the arcs.

Fig. 9 shows an additional form of auxiliary arc member which may be used in a similar manner to the are members l6 of Fig. 1. Generally, it may comprise a U-shaped member 53 having a runner portion 54 and upstanding side flanges which are adapted to encompass the insulating member and be secured in engagement at the upper ends by a bolt 57. These are members are adapted to be positioned on the insulating member in spaced relation and are associated in paired relation by resistance elements 58, disposed to provide a path of relatively high resistance for an arc current between the auxiliary arc members of a pair.

As a current collector traverses the section insulator, an arc will be drawn from the arc tip 30 of the renewable arc member 15. As the current collector further traverses the section insulator, the arc will be drawn to the first auxiliary arc member 53, and as the current collector reaches the second arc member, the arc current will follow the conducting path through the first arc member 53, resistance member 58 and the second arc member 53. In this manner, the direction of current flow adjacent an arc will be substantially perpendicular to the axis of the arc, and a downwardly repellant magnetic field will therefore be reactive on the arc to extinguish it. The resistance member 58 serves to further weaken the are by limiting the flow of are current, thus further aiding in the arc extinction.

By incorporating a number of pairs of are members in spaced relation along a section insulator or other insulating fixture, the desired are extinguishing characteristics may be obtained.

It may, therefore, be seen that by my invention I have provided means for the protection of the insulating member of a section insulator which may readily be applied even to insulators already in service. It is further, not only simple and inexpensive to manufacture, but easily installed and economical to maintain, effectively repelling an are drawn by a current collector from contact with the insulating member and substantially increasing the life of the insulating material.

Since certain changes may be made in the above description and different embodiments of the invention without departing from the spirit thereof, it is intended that all the matter shown in the accompanying drawings or contained in the above description shall be considered as illustrative and not in a limiting sense.

I claim as my invention:

1. The combination in a section insulator for an overhead trolley system of, an insulating member, end members adapted to position the insulating member, a transversely slotted current directing arc member associated with an end member, and means including an auxiliary runner arc member for providing a conducting path for an arc current cooperative with said arc member to magnetically repel an are from the insulating member.

2. A section insulator for an overhead trolley system comprising the combination of an insulating member, support means secured to the ends of the insulating member, and a plurality of transversely slotted metallic runner members disposed in spaced relation on the insulating member to provide upwardly looped paths for the current of an are drawn between said runner members by a current collector, the magnetic field about said paths being disposed to downwardly repel an are from the insulating member.

3. A section insulator comprising, in combination, an insulating member, end members adapted to position the insulating member in operating relation, a renewable arc member associated with an end member and provided with an upwardly extending transverse slot disposed to form a downwardly projecting arc tip, and a plurality of upwardly transversely slotted metallic runner members disposed on the insulating member in spaced relation adapted to break an are drawn by a current collector into a plurality of serially related arcs and provide a magnetic field disposed to repel an are from the insulating member.

4. The combination in a section insulator for an overhead trolley system comprising, an insulating member, end members adapted to position the insulating member, a transversely upwardly slotted renewable arc member associated with an end member, a renewable insulating runner member, an auxiliarymetallic arc member associated with the runner member, and arc current conducting means of relatively high resistance in series circuit relation with the renewable arc member and the auxiliary arc member adapted to limit the current in an are drawn by a current collector and provide a magnetic field disposed to downwardly direct an are drawn by a passing current collector.

5. The combination in a section insulator of, an insulating strain member, end members adapted to secure the insulating member in an overhead trolley system, a renewable slotted arc member associated with an end member, said slot being disposed to provide a downwardly directive path for an arc current adjacent the end of the arc member, and a plurality of auxiliary metallic arc members disposed along the insulating member in association with a runner member to provide a plurality of serially related arc gaps, said auxiliary are members being upwardly slotted to provide a looped path for an arc current, thereby providing an arc repellant magnetic field on transition of a current collector.

6. A section insulator comprising, in combination, an insulating strain member, end members in association with the strain member, an arc terminal member associated with an end member having an upwardly extending slot adapted to provide a downwardly directive path for an electric arc current, and a plurality of spaced metallic runner members associated in paired relation by integral conducting portions adapted to provide upwardly looped current paths for an arc current thereby providing a magnetic field disposed to downwardly direct an electric are drawn in the passing of a current collector along the insulator.

7. The combination in a section insulator for an overhead trolley system of an insulating member, end members adapted to secure the insulating member in operating relation in the overhead system, a renewable metallic arc member associated with an end member and provided with an upwardly extending transverse slot to form a downwardly extending arc tip, a renewable metallic runner member disposed in spaced relation to said are tip, and arc current conducting means disposed in series circuit relation with the runner member and the arc member, comprising a plurality of turns of a metallic ribbon of relatively high resistance positioned along the sides of the insulating member adapted to limit an are current and produce a magnetic field disposed to repel an are from the insulating member.

8. A section insulator comprising, in combination, an insulating member, end members to support said member, an arc terminal member having an upwardly extending transverse slot associated with an end member, and a transversely slotted arc member comprising a pair of spaced metallic runner portions with upstanding integral looped connector portions about the insulating member, said are member being in spaced relation with the arc terminal member to provide a metallic path for an arc current and produce an arc repellant magnetic field.

9. The combination in a section insulator for an overhead trolley system of, an insulating body member, end means adapted to position the body member in an overhead system, a transversely upwardly slotted arc member associated with an end means for directing the path of an arc current, a renewable metallic runner arc member disposed in spaced relation with said slotted arc member, and means comprising a metallic path for an arc current disposed in series circuit relation with the end means and the renewable arcing member to provide a relatively substantial voltage drop between the end means and the runner arcing member and provide an arc repelling magnetic field.

10. A section insulator for an overhead trolley system comprising, in combination, an insulating body member, end members adapted to secure the body member in operating relation, and means including a plurality of transversely slotted metallic runner members adapted to break an are drawn by a current collector into a plurality of serially related arcs, said members being slotted to provide an upwardly looped path for the arc current and operable to produce an arc repelling magnetic flux.

11. A section insulator for an overhead trolley system comprising, in combination, an insulating member, end members adapted to position the insulating member, and a metallic runner member transversely slotted to provide an upwardly looped path for the current of an electric arc drawn by a passing current collector, the magnetic field about the current path being disposed to downwardly repel the arc from the insulating member.

12. The combination in a section insulator of an insulating member, end members adapted to position the insulating member, an arc terminal member upwardly slotted to provide an electric arc current path substantially perpendicular to the axis of the insulator associated with an end member, a plurality of runner members disposed in spaced relation along the insulating member, and metallic conducting paths integral with the runner members disposed to associate the runner members in paired relation and to provide upwardly looped metallic paths about the insulating member for an arc current whereby a magnetic field repellant to an arc along the insulating member is provided while said are current flows.

13. The combination in a section insulator of an insulating strain member, end members adapted to position the strain member, an upwardly transversely slotted arc member associated with an end member, a metallic runner arc member disposed in spaced relation with said slotted arc member, and are controlling means including an elongated coil of relatively high resistance disposed to be positioned in divided relation about the insulating member in series circuit relation with the slotted arc member and runner arc member to provide a potential differential between said members and a magnetic field disposed to downwardly repel an electric are when an arc is drawn by a passing current collector.

14. A section insulator comprising, in combination, an insulating strain member, end means adapted to position the insulating member, a plurality of metallic are members having upstanding sides disposed in spaced relation along the insulating member to provide spaced metallic runner portions, and connector members of relatively high resistance disposed to associate said upstandin sides to connect the auxiliary are members in paired relation for substantially limiting the flow of arc current between pairs of auxiliary arc members and providing upwardly looped arc current paths therethrough.

CHARLES C. WHITTAKER. 

